Device for controlling the refining load of a disk refiner



1969 A. J. YLI-PAAVOLA DEVICE FOR CONTROLLING THE REFINING LOAD m Illll' H OF A DISK REFINER Filed Dec.

ml Hll INVENTOR A NTTJ JuHA NI V1. 1- PA A VoLA United States Patent Ofiice 3 Claims ABSTRACT OF THE DISCLOSURE A device for controlling the refining load in a disk refiner wherein the material being refined is worked between closely spaced opposed disks, the control being effected by a pressure medium acting in a chamber in back of the disk. The disk itself acts as a piston operating within a cylinder formed by the cover receiving it.

Background In disk refiners, where the bar clearance can be fixedly adjusted, variations in stock consistency cause an uneven refining effect. In order to eliminate this drawback disk refiners have been designed and made, where the bar clearance has been arranged to be hydraulically or pneumatically controlled. This has been achieved by fitting hydraulic or pneumatic control devices at the ends of the refiner disk shafts, whereby the construction has become one of unproportional space requirement and has led to the use of unproportionally high pressures (see for instance the Swedish patent publication No. 172,313). Mechanical control devices have also been used, but with them sufiicient resiliency, necessary because of consistency variations of the stock to be refined, cannot be attained. 3

(See the Finnish patent publications Nos. 31,185 and 30,431,)

With a device according to the present invention the above-mentioned drawback can be eliminated and the refining pressure or the refining load be kept constant irrespective of the variations in the consistency of the stock to be refined, while keeping the size of the disk refiner smaller and above all, using lower refining pressures.

Summary of the invention The device of the invention controls the refining load in a disk refiner of the type having two refiner disks positioned against each other and being rotatable with respect to each other. Such a control is effected by pressing one, or both of the disks, against the other with a controllable pressure utilizing a pressure medium so that the refining pressure, or refining load, is kept at a constant desired value regardless of variations during the refining operation in the consistency, quality, or feed rate of the stock being refined. This is done by having the refining bar disk itself fitted like a piston in a cover formed into a cylinder to receive it. The pressure medium is introduced into the space or chamber behind the disk and the control of the pressure exerted by the pressure medium in turn controls the movement of the disk.

It is accordingly the object of the invention to provide for refining or fiberizing either under conditions of constant refining pressure, constant motor power input, or constant bar clearance.

In the following the invention is more fully described with reference to the accompanying drawing, which, as an example, presents the construction of the stationary disk of a disk refiner according to the invention together with the device according to the invention, in longitudinal section. The construction of the rotating disk may be of a type known per se.

3,420,458 Patented Jan. 7, 1969 The drawing refers to a non-rotationally mounted stationary bar disk,provided at its center with a feeding aperture 2 for feeding the stock to be refined between the bar disks by means of a feeding screw 3. The disk 1 is fitted in the manner of a piston inside a cylindrical stationary cover 4 so that between the disk 1 and the cover 4 is formed a chamber 5 for a pressure medium.

The feeding aperture 2 is constituted by a tube 6, situated concentrically with the disk and consisting of the same material, the wall of which penetrates cover 4 centrally and is tightened against the cover. For stock feed a feed connection 7 is fitted inside the tube 6 and similarly tightened against the inner surface of the tube 6. The end of tube 6 penetrating cover 4 is provided with a worm gear 8 whose body is threaded with respect to the protruding part of the tube 6, rotates against the side of the fixed ring 11 and which serves to limit the movement of disk 1 with respect to the back edge 10 of the cover 4, as the disk 1, is moving towards a rotating refiner disk 12 carried by the axle 13 within the cover 14 mated with the cover 4 to form the housing in which the disks operate on the feed.

The pressure medium is introduced into the chamber 5 through line 9 which may be water at ordinary water main pressure. A pressure gauge or meter 15 shows this pressure which may be controlled by a valve 16. A pump 17 may be used if higher pressure is desired. As can be seen from the drawing, the surface exposed to the pressure medium, of the bar disk serving as a piston, is comparatively great, which makes it possible to get by with low pressure hydraulics and to avoid unproportionately high pressures.

By subjecting the pressure medium in chamber 5 to a suitable pressure for each particular refining operation, a homogenous refining effect is achieved by virtue of the resiliency of the disk and the response of the same to the behind it, irrespective of variations in the consistency, the quality, or the feeding rate of the stock fed to the refiner during the refining operation, and irrespective of potential disturbances in the distribution of the fed stock on the bar region.

The invention is not limited to the construction described above and shown in the drawing, which can be varied in many ways within the scope of the appended claims; so, for instance, the refiner disk 1 can also be mounted for rotation, and either both or only one of the refiner disks be provided with the above-described pressure medium control. Since these solutions, however, must be considered, on the basis of the above description, to be self-evident for an expert, they have not been shown in the drawing.

What we claim is:

1. A device for controlling the refining load in a disk refiner comprising two refiner disks positioned against each other and being in a state of rotational movement relative each other, the bar clearance between said disks being adapted to be controlled by pressing one or both of the disks against the other with a controllable pressure created by means of a pressure medium so that the refining pressure or the refining load is kept at a constant desired value irrespective of variations during the refining operation in the consistency, the quality, or the feed rate of the stock being refined, characterized in that the bar disk (1) is fitted in the manner of a piston in a cover (4) formed as a cylinder and being open at its end facing the same way as the bars of the bar disk (1), so that a chamber (5) is formed between the bar disk 1) and the cover (4) for a pressure medium, the pressure of which can be controlled to a desired value in a manner known per se.

2. A device according to claim 1, characterized in that only one of the refiner disks is mounted for rotation and 3 the control is achieved by means of the un-rotating, stationary disk.

3. A device according to claim 1 characterized by means for limiting the movement against each other of the bar disks.

References Cited UNITED STATES PATENTS 1,065,332 6/1913 Newhouse 241-251 2,412,680 12/1946 Fisher et a1 241-256 Sullivan 241-256 Iohansson 2441-37 Fisher 241-290 Laird 241-32 Bakewell 241-286 Marco 241-37 China 241-37 Dalzell et al 241-290 GERALD A. DOST, Primary Examiner. 

